An X-ray data search of nearby galaxies NGC 4636 and NGC 5128 uncovers two sources of ultraluminous X-ray flares
from sources not associated with the galactic centres [1]}.
All these X-ray bursts have similar rise time, which is less than one minute and the decay time of about an hour.
The first source flared once, with an estimated peak X-ray luminosity of \(9 \times 10^{40}\) erg s\(^{-1}\) , while the second flared five times and it was \(\sim 10\)  times
weaker. Prior to and after the flare, a 0.3-10 keV luminosity of the first source was of \(7.9 \times 10^{38}\)  erg s\(^{-1}\)  and \(4 \times 10^{37}\)  erg s\(^{-1}\)  in the case of the second source.
